http://imageshack.com/a/img33/5853/ge7y.gif [Broken] In the above diagram,the part 3 the planetary wheel(its not the gear at the input or output side but in the middle of the differential). I call it the planetary wheel because I consider a bevel gear differential just an approximation of a planteary gear differential with equal radii of ring and sun gears. First of all,I want to clarify: 1.A open differential transfers equal power to the left and right wheels,right? P_left=P_right I make this presumption because when taking a turn,the angular velocities of the wheel are different and hence to make the power equal,I would need to vary the torques.I mean: M_left * ω_left =M_right *ω_right So,if ω_left<ω_right => M_left > M_right Am I right with this logic? 2. If the above logic is correct, in the above diagram the force [F_E /2] would vary at the left and right wheels. If [F_E/2] were equal,the planetary gears would revolve and not rotate around their axis(straight line driving). But,in case of the turns, what would the force magnitude at the planetary wheel be(marked with a question mark in above diagr.)? I presume this would be [F_left-F_right]. Am I correct?